Planar lightwave circuits based on silicon are playing an important role in integrated optical systems. The integrated waveguide turning mirror (IWTM) is an essential component for the compactness of optical devices. We have designed such a mirror with a 90/spl deg/ directional change in silicon-on-insulator (SOI). The fabricated mirror has very small surface roughness. The loss caused by transverse tilt /spl delta//sub t/ and lateral tilt /spl delta//sub l/ is negligible in theory. A 1 /spl times/ 2 beam splitter using the structure is fabricated to test the performance, and turning mirrors of excess loss less than 0.5 dB/mirror are obtained.

Integrated waveguide turning mirror in silicon-on-insulator

The invention is directed to an optically pumped surface-emitting semiconductor laser device having at least one radiation-generating quantum well structure and at least one pump radiation source for optically pumping the quantum well structure, whereby the pump radiation source comprises an edge-emitting semiconductor structure. The radiation-generating quantum well structure and the edge-emitting semiconductor structure are epitaxially grown on a common substrate. A very efficient and uniform optical pumping of the radiation-generating quantum well structure is advantageously possible with this monolithically produced semiconductor laser device. Methods for manufacturing inventive semiconductor laser devices are also specified.

Optically pumped, surface-emitting semiconductor laser device and method for the manufacture thereof

We demonstrate InGaAsP-InP nanoscale waveguide-coupled microring lasers fabricated with inductively coupled plasma (ICP) using Cl/sub 2/--N/sub 2/-based gas mixtures. To fabricate optical waveguides, the requirement of anisotropic profiles and sidewall smoothness is stringent. In particular, for strongly lateral confined nanoscale waveguides used for microring resonators, the degree of anisotropy and sidewall smoothness is critical in determining the device performance. For optoelectronic devices such as microcylinder and microring lasers, the requirement of low active-layer damage further adds to the stringency. We show that the excellent etching property of high-density plasma using Cl/sub 2/--N/sub 2/-based gas mixtures satisfies the requirements. The good etching results are demonstrated by using the etching method to realize room-temperature operations of the InGaAsP-InP waveguide-coupled microring lasers. For the waveguide-coupled microring lasers with a diameter of 10 /spl mu/m, we obtained submilliampere threshold current.

InGaAsP-InP nanoscale waveguide-coupled microring lasers with submilliampere threshold current using Cl/sub 2/--N/sub 2/-based high-density plasma etching

A new type of vertical-cavity surface-emitting laser (VCSEL) is proposed and analyzed to show the possibility of optical pumping from an integrated edge-emitting laser. With this scheme, it may be possible to make VCSEL's of very small dimensions and VCSEL arrays. The laser design utilizes dopant induced intermixing of quantum wells (QW's) to provide different gain regions for the surface and edge-emitting sections. The multimode rate equations are used to evaluate the possibility of such a laser and the roles of the various design parameters are discussed. It is seen that efficient surface photon emission is possible for high vertical-cavity mirror reflectivities and sufficient separation of bandgap energies for the two QW gain regions.

Novel design of a hybrid-cavity surface-emitting laser

An improved optical transmitter comprises a vertically lasing semiconductor optical amplifier (VLSOA) coupled to an external modulator and/or a laser source. The VLSOA, external modulator and laser source are discrete devices or alternatively integrated onto a common substrate. The integrated optical transmitter may be fabricated using a number of different methods, including based on selective area epitaxy, impurity induced disordering, etch and fill and silicon optical bench.

Optical transmitter including a linear semiconductor optical amplifier

We report the observation of optical control of the stimulated emission of a vertical cavity surface emitting laser (VCSEL) by an intra‐cavity coupled in‐plane laser. Depending on the overlap between the two gain regions, greater than 70% change in threshold current to complete quenching of the VCSEL, is observed. The combined device offers a wide variety of potential applications for integrated, all‐optical logic devices and optical interconnects between signal planes.

Gain controlled vertical cavity surface emitting lasers coupled with intracavity in-plane lasers

Etched laser mirrors are important for the monolithic integration of lasers in optical circuits without cleaved facets. Electron cyclotron resonance (ECR) etching is ideal for opto-electronic fabrication since the etching parameters are independently adjustable and a variety of masking materials are available for creating multiple etch depths, e.g., for etched ridge lasers with etched mirror facets. We report on the fabrication and characterization of ECR etched laser mirrors and waveguides. The quality of the ECR etch is ascertained by measuring the reflection coefficients of 90/spl deg/ turning mirrors in GaAs-AlGaAs multiple-quantum-well (MQW) lasers incorporating multiple numbers of 90/spl deg/ bends. The average reflection coefficient is found to be approximately 80%. >

Electron-cyclotron resonance etching of mirrors for ridge-guided lasers

An in situ method of monitoring the electron cyclotron resonance etching of III-V semiconductor heterostructures is discussed for in-plane lasers. Surface reflected and Fabry-Perot interference signals determine the etch depth, rate and surface quality. The etching accuracy is better than 500 /spl Aring/. The etch monitor eliminates the dependence of accurate etching on calibrated etch rates, as well as the need for selective gas etchants and etch-stop layers typically required for complex heterostructure devices. The presented in situ method can be integrated into a digital data acquisition system, for accurate, reproducible process control in an automated manufacturing environment.

Accurate electron-cyclotron-resonance etching of semiconductor laser heterostructures using a simple laser reflectometer

An in situ laser reflectometer is used to determine the surface roughness of III–V laser heterostructure as it etches in an electron cyclotron resonance etcher. A stochastic model links the reflectometer signals with the fluctuations of the surface height and slope, and with the size of the illuminated surface area. This technique is valuable for improving the quality of optical waveguides etched in III–V heterostructure, and the electrical contacts for optoelectronic devices.

Etched‐surface roughness measurements from an in situ laser reflectometer

A thread-safe data store has been developed to enforce interface consistency and shared data coherency in a concurrent modular embedded real-time system. Typical messaging techniques may not provide optimal data transfer between software components in all embedded systems, especially if there is a high degree of data interdependency as the number of components increases. The data store paradigm reduces the overall communication load by providing finer data item granularity, and eliminating the copy and transfer of unused message content. The data store described in this paper is implemented with code auto-generation and provides compile-time error checking, ensuring effortless data integrity by automatically rebuilding when software component interfaces are changed. The data store has been successfully employed to rehost a highly-coupled legacy software application into a more modularized component architecture.

J. S. Kimmet

Papers

Gain controlled vertical cavity surface emitting lasers coupled with intracavity in-plane lasers

Electron-cyclotron resonance etching of mirrors for ridge-guided lasers

Accurate electron-cyclotron-resonance etching of semiconductor laser heterostructures using a simple laser reflectometer

Etched‐surface roughness measurements from an in situ laser reflectometer

Auto-Generated Coherent Data Store for ConcurrentModular Embedded Systems